Storage type water heater

Abstract

To promptly discharge air accumulated in the upper part of a hot water storage tank to a bathtub.SOLUTION: When hot water filling operation is started, opening control means 35 sets an opening of an intermediate temperature water mixing valve 5 to a high-temperature side full opening and sets an opening of a bath mixing valve 28 to a feedback opening calculated from a hot water filling temperature, and hot water filling operation control means 36 performs a predetermined amount of hot water filling operation. When the predetermined amount of hot water filling is completed, the opening control means 35 switches the opening of the intermediate temperature water mixing valve 5 to an opening for using intermediate temperature water positively, and the hot water filling operation control means 36 performs the hot water filling operation until a hot water filling set amount is reached. Due to this configuration, air can be discharged to a bathtub safely, and at an initial time of the hot water filling operation, air accumulated in the upper part of a hot water storage tank can be discharged completely.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a storage type hot water supply device having a heating means. [Background technology]

[0002] Conventionally, this type of hot water storage type water heater has been equipped with a hot water storage tank and a heating means, and a heating circulation circuit is formed by connecting the hot water storage tank and the heating means with a heating forward pipe that sends water from the bottom of the hot water storage tank to the heating means and a heating return pipe that sends water from the heating means to the hot water storage tank.A circulation pump provided in the heating circulation circuit circulates hot water in the hot water storage tank and the heating means, and the hot water boiled during the boiling operation that heats the water in the hot water storage tank is stored in the hot water storage tank.The high-temperature water in the hot water storage tank is sequentially mixed with the supply water to provide hot water at the set temperature, thereby achieving economical hot water supply.

[0003] It was also known that by positioning a pressure relief valve, which opens when the pressure inside a storage type hot water supply system exceeds a predetermined pressure, in a position where low-temperature water flows, low-temperature water is discharged when the pressure is released outside the storage type hot water supply system, thereby preventing high-temperature water stored in the hot water storage tank from being discharged outside the storage type hot water supply system (for example, Patent Document 1).

[0004] It is also known that the high temperature side of a medium temperature water mixing valve is opened to release air accumulated in a hot water storage tank to a hot water supply terminal, making it easier to release the air (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-217622 A [Patent Document 2] JP 2016-211811 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, by locating a pressure relief valve in the water supply pipe as in Patent Document 1, it is possible to prevent the discharge of high-temperature water when the pressure inside the hot water tank becomes high during boiling operation. However, because the pressure relief valve is located at the bottom of the hot water tank, there was an issue in that it was not possible to discharge the air that was discharged along with the pressure that had accumulated at the top of the hot water tank.

[0007] In addition, simply opening the high temperature side of the medium temperature water mixing valve to make it easier to escape the air, as in Patent Document 2, had the problem that it took a long time for the air that had accumulated at the top of the hot water storage tank to escape. [Means for solving the problem]

[0008] According to the present invention, there is provided a hot water storage tank for storing hot water, a water supply pipe connected to a lower part of the hot water storage tank, heating means for heating the hot water in the hot water storage tank, a heating forward pipe for sending water from the lower part of the hot water storage tank to the heating means, a heating return pipe for sending water from the heating means to an upper part of the hot water storage tank, a pressure relief valve provided in a pipe connected to the lower part of the hot water storage tank for releasing pressure to the outside of the hot water storage tank when the pressure in the hot water storage tank exceeds a predetermined pressure, a water supply bypass pipe branched off from the water supply pipe, a medium temperature water mixing valve for mixing high temperature water taken out from the upper part of the hot water storage tank and medium temperature water taken out from a middle part of the hot water storage tank, a bath mixing valve for mixing the medium temperature water mixed by the medium temperature water mixing valve and the supply water from the water supply bypass pipe and supplying the water to a bathtub, a hot water mixing valve for mixing the medium temperature water mixed by the medium temperature water mixing valve and the supply water from the water supply bypass pipe and supplying the water to a hot water tap, and a water supply valve for mixing the medium temperature water mixed by the bath mixing valve and the supply water from the water supply bypass pipe and supplying the water to a hot water tap. In a storage-type hot water supply device equipped with a control device having a filling temperature sensor that detects the filling temperature of the hot water combined with the medium temperature water, a filling path that supplies the mixed water mixed in the bath mixing valve to the bathtub, a filling operation control means that performs a filling operation to supply a predetermined arbitrary filling amount of hot water to the bathtub via the filling path, and an opening control means that controls the opening of the medium temperature water mixing valve and the bath mixing valve, when the filling operation is started, the opening control means opens the medium temperature water mixing valve fully to the high temperature side and sets the opening of the bath mixing valve to a feedback opening calculated from the filling temperature, and the filling operation control means performs a predetermined amount of filling operation, and when the predetermined amount of filling is completed, the opening control means switches the opening of the medium temperature water mixing valve to an opening that actively uses the medium temperature water, and the filling operation control means performs the filling operation until the set filling amount is reached.

[0009] In addition, when the hot water supply operation of the hot water mixing valve and the bath mixing valve are used simultaneously to fill the bath with the specified amount of hot water, the opening control means switches the opening of the medium temperature water mixing valve to an opening that actively uses the medium temperature water to fill the bath with the specified amount of hot water, and if the hot water supply operation ends in the middle of filling the bath with the specified amount of hot water, the opening control means opens the medium temperature water mixing valve fully to the high temperature side to continue filling the bath with the specified amount of hot water.

[0010] In addition, the opening control means prevents the opening of the medium temperature water mixing side of the bath mixing valve from exceeding a predetermined upper limit opening. Effect of the Invention

[0011] According to this invention, when a specified amount of water is filled at the beginning of the filling operation, the medium temperature water mixing valve is fully opened to the high temperature side and the bath mixing valve is opened to a feedback opening calculated from the filling temperature, thereby discharging the air that has accumulated at the top of the hot water storage tank into the bathtub. This allows the air to be safely discharged into the bathtub and also allows all the air that has accumulated at the top of the hot water storage tank to be completely discharged at the beginning of the filling operation. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram showing an embodiment of the present invention. [Diagram 2] 4 is a flowchart showing the operation of the filling operation of the present invention. [Diagram 3] 4 is a flowchart showing the operation of the present invention when the hot water filling operation and the hot water supply operation are used simultaneously. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Next, a storage type hot water supply device according to one embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes the hot water storage tank unit, inside which are provided a hot water storage tank 2 for storing hot water, a high temperature side hot water outlet pipe 3 connected to the top of the hot water storage tank 2, a medium temperature side hot water outlet pipe 4 connected to the middle of the hot water storage tank 2, a medium temperature water mixing valve 5 for mixing high temperature water from the high temperature side hot water outlet pipe 3 and medium temperature water from the medium temperature side hot water outlet pipe 4, a water supply pipe 6 connected to the bottom of the hot water storage tank 2, a hot water mixing valve 8 for mixing the mixed water from the medium temperature water mixing valve 5 and low temperature water from a water supply bypass pipe 7 branched off from the water supply pipe 6, and a hot water temperature sensor 10 and a hot water flow sensor 11 for detecting the hot water flow rate, which are provided in a hot water pipe 9 connected downstream of the hot water mixing valve 8.

[0014] Reference numeral 12 denotes a heat pump unit, which includes a heat pump type heating means 18 consisting of a compressor 13, a water-refrigerant heat exchanger 14 as a condenser, an electronic expansion valve 15, an outdoor fan 16, and an air heat exchanger 17 as an evaporator that exchanges heat with air, a circulation pump 22 that circulates hot water in the hot water storage tank 2 to the heating means 18 via a heating circulation circuit 21 consisting of a heating supply pipe 19 and a heating return pipe 20, and a heat pump control unit 23 that controls the operation of these, and carbon dioxide is used as a refrigerant in the heating means 18 to form a supercritical heat pump cycle. In addition, because carbon dioxide is used as the refrigerant, it is possible to boil low-temperature water to a high temperature of about 90°C without an electric heater.

[0015] Here, the water-refrigerant heat exchanger 14 employs a counterflow system in which the refrigerant and the hot water in the hot water storage tank 2, which is the water to be heated, flow in opposite directions, and in a supercritical heat pump cycle, the refrigerant is condensed while remaining in a supercritical state during heat exchange, so the water to be heated can be heated to a high temperature efficiently, and by controlling the expansion valve 15 or compressor 13 so that the temperature difference between the inlet temperature of the heated water into the water-refrigerant heat exchanger 14 and the outlet temperature of the refrigerant is constant, it is possible to heat the heated water with a very good COP (coefficient of performance) when the inlet temperature of the heated water into the water-refrigerant heat exchanger 14 is a low temperature of around 5 to 20°C.

[0016] In addition, a heating bypass valve 24 is provided midway through the heating return pipe 20, and during freezing prevention, the heating bypass valve 24 is switched to communicate with the heating bypass pipe 25 side, which is a heating bypass path connected to the water supply pipe 6 at the bottom of the hot water storage tank 2, thereby preventing freezing by circulating a short circuit using the bottom of the hot water storage tank 2. This heating bypass valve 24 is disposed at the branch point from the heating return pipe 20 to the heating bypass pipe 25.

[0017] In addition, when circulating hot water that is not sufficiently heated at the beginning of heating by the heating means 18, the hot water is not returned to the top of the hot water storage tank 2, but is returned to the bottom of the hot water storage tank 2 via a bypass circulation path via the heating bypass pipe 25, and when circulating hot water that is sufficiently heated thereafter, the heating bypass valve 24 is switched to the top side of the hot water storage tank 2.

[0018] Reference numeral 26 denotes a pressure reducing valve provided in the water supply pipe 6.

[0019] Reference numeral 27 denotes a pressure relief valve provided in the heating bypass pipe 25 for relieving pressure within the hot water storage tank 2 and the heating circulation circuit 21.

[0020] This pressure relief valve 27 opens when the hot water in the hot water storage tank 2 and the heating circulation circuit 21 becomes hot during heating operation, causing the pressure inside the storage type hot water supply system to rise and exceed a certain pressure, and the hot water along with the pressure is discharged outside the storage type hot water supply system.

[0021] Reference numeral 28 denotes a bath mixing valve that mixes mixed water from the medium temperature water mixing valve 5 and low temperature water from the water supply bypass pipe 7 branched off from the water supply pipe 6.

[0022] Also, 29 is a filling valve that connects the filling pipe 30 to the bathtub 31 to supply hot water to the bathtub 31, 32 is a filling temperature sensor that detects the filling temperature supplied to the bath, and 33 is a bath flow sensor that detects the flow rate that passes through the filling pipe 30. The filling path is a path that supplies hot water to the bathtub 31 in the following order: the hot water storage tank 2, the medium temperature water mixing valve 5, the bath mixing valve 28, and the filling pipe 30.

[0023] Reference numeral 46 denotes hot water temperature sensors provided outside the hot water storage tank 2, and are provided at predetermined intervals from the top to the bottom of the hot water storage tank 2, and are an upper hot water temperature sensor 46a, an intermediate hot water temperature sensor 46b, a second intermediate hot water temperature sensor 46c, and a lower hot water temperature sensor 46d, from the top. The intermediate hot water temperature sensor 46b detects the temperature of the medium-temperature water in the hot water storage tank 2.

[0024] Reference numeral 47 denotes a mixed water temperature sensor that detects the temperature of the mixed water from the medium temperature water mixing valve 5 , and 48 denotes a supply water temperature sensor provided in the water supply pipe 6 that detects the supply water temperature.

[0025] Reference numeral 34 denotes a control device consisting of a microcomputer etc., which controls the heat pump control unit 23 to perform operation control such as heating operation and reheating operation of the hot water storage tank 2 using the heating circulation circuit 21, hot water temperature control, filling the bathtub with water, reheating the bathtub, and keeping the bathtub warm.

[0026] The control device 34 also has an opening control means 35 that controls the opening of the medium temperature water mixing valve 5 and the bath mixing valve 28. Specifically, the opening control means 35 calculates the opening of the medium temperature water mixing valve 5 and the bath mixing valve 28, and drives the valves to the calculated opening.

[0027] For example, the opening control means 35 can fix the opening by specifying the ratio of the opening of the high temperature side and the low temperature side of the medium temperature water mixing valve 5 and the bath mixing valve 28.

[0028] The opening control means 35 can also use the calculated feedforward opening to control the opening. For example, in the case of the bath mixing valve 28, the opening control means 35 calculates the feedforward opening of the bath mixing valve 28 according to the mixed water temperature detected by the mixed water temperature sensor 47, the supply water temperature detected by the supply water temperature sensor 48, and the predetermined bath filling temperature setting, and controls the opening of the bath mixing valve 28 to the calculated feedforward opening.

[0029] Also, explaining the medium temperature water mixing valve 5, the opening control means 35 calculates the feedforward opening of the medium temperature water mixing valve 5 in accordance with the temperature detected by the upper hot water storage temperature sensor 46a and the intermediate hot water storage temperature sensor 46b provided outside the hot water storage tank 2 and the mixed water set temperature, which is the set temperature of the mixed water mixed in the medium temperature water mixing valve 5, and controls the opening of the medium temperature water mixing valve 5 to the calculated feedforward opening.

[0030] In addition, the feedforward opening degree calculates the opening degree of the medium temperature water mixing valve 5 according to the temperatures detected by the upper hot water storage temperature sensor 46a and the intermediate hot water storage temperature sensor 46b. When the temperature near the medium temperature side hot water outlet pipe 4 detected by the intermediate hot water storage temperature sensor 46b is higher than the hot water supply set temperature or the hot water filling set temperature, the medium temperature water mixing valve 5 opens 100% on the medium temperature side, and when the temperature detected by the intermediate hot water storage temperature sensor 46b falls below the hot water supply set temperature or the hot water filling set temperature, the medium temperature water mixing valve 5 opens the high temperature side so that the mixed water temperature detected by the mixed water temperature sensor 47 is equal to or higher than the hot water supply set temperature or the hot water filling set temperature. In this way, the feedforward control of the medium temperature water mixing valve 5 allows the medium temperature water to be used more actively than the high temperature water at the top of the hot water storage tank 2.

[0031] The opening control means 35 can also use the calculated feedback opening to control the opening. For example, in the case of the bath mixing valve 28, the feedback opening is calculated so that the actual filling temperature mixed by the bath mixing valve 28 becomes the preset filling temperature, and the feedback opening is controlled so that the temperature detected by the filling temperature sensor 32 becomes the preset filling temperature.

[0032] The control device 34 is also provided with a water filling operation control means 36 for controlling the water filling operation described below, and a water boiling operation control means 37 for controlling the water boiling operation described below.

[0033] The remote control 38 further has a temperature setting switch 39 for setting the hot water supply temperature, a water filling switch 40 for instructing the bathtub 31 to be filled with water, and a water filling amount setting switch 41 for setting the amount of water to be filled, and is further equipped with a display unit 42 consisting of a dot matrix type fluorescent display tube, and a remote control control unit 43 consisting of a microcomputer that controls the display unit 42 and communicates with the control device 34.

[0034] Next, the boiling operation will be described. When there is a decrease in the heat energy of the stored hot water or a request for heating during the middle of the night, the heating operation control means 37 switches the heating bypass valve 24 to a first state in which it connects to the lower side of the hot water storage tank 2, and the control device 34 drives the circulation pump 22 located in the middle of the piping connecting the hot water storage tank 2 and the heating means 18 to pump water from the lower part of the hot water storage tank 2, heat it in the heating means 18, and return it to the lower part of the hot water storage tank 2, and then switches to a second state in which it connects to the upper side of the hot water storage tank 2, and by continuing the operation of returning the water to the upper part of the hot water storage tank 2, the water in the hot water storage tank 2 is gradually boiled into high-temperature water.

[0035] By performing the boiling operation, the water in the hot water tank 2 becomes hot and the pressure in the hot water tank 2 rises, so during the boiling operation, hot water is discharged from the pressure relief valve 27 to the outside of the hot water supply device together with the pressure. At this time, the air dissolved in the water accumulates in the upper part of the hot water tank 2.

[0036] Next, the hot water supply operation will be described. When the hot water tap is opened, water is supplied from water supply pipe 6, flows into the bottom of the hot water storage tank 2, and passes through water supply bypass pipe 7 on the hot water mixing valve 8 side. The high temperature water pushed out from the top of the hot water storage tank 2 and the medium temperature water pushed out from the middle of the hot water storage tank 2 are mixed in the medium temperature water mixing valve 5. The mixed water mixed in the medium temperature water mixing valve 5 and the water supply from the water supply bypass pipe 7 on the hot water mixing valve 8 side are mixed in the hot water mixing valve 8. Hot water adjusted so that the hot water setting temperature and the temperature detected by the hot water temperature sensor 10 are the same is supplied from the hot water tap.

[0037] Next, the filling operation will be described. When the filling switch 40 on the remote control 38 or the automatic operation switch (not shown) is pressed, the filling operation control means 36 opens the filling valve 29, supplies water from the water supply pipe 6, and the water flows into the bottom of the hot water storage tank 2 and passes through the water supply bypass pipe 7 on the bath mixing valve 28 side. The high-temperature water pushed out from the top of the hot water storage tank 1 and the water supply from the water supply bypass pipe 7 on the bath mixing valve 28 side are mixed in the bath mixing valve 28, and the hot water adjusted so that the filling set temperature and the temperature detected by the filling temperature sensor 32 are the same is flowed into the bathtub 31, starting filling. The bath flow sensor 33 then detects the flow rate, and when the total accumulated value of the flow rate reaches the filling set amount, the filling operation control means 36 closes the filling valve 29, ending the filling operation.

[0038] Next, the discharge of air accumulated in the upper part of the hot water tank 2 will be described in detail with reference to the flow chart of FIG. When the filling switch 40 on the remote control 38 or an automatic operation switch (not shown) is pressed, the filling operation control means 36 starts the filling operation (S1 is Yes).

[0039] The opening control means 35 controls the opening of the medium temperature water mixing valve 5 at a ratio of 100% for the high temperature side connected to the top of the hot water tank 2 and 0% for the medium temperature side connected to the middle of the hot water tank 2 (S2), and starts a predetermined amount of water filling operation (5L in this case) with a feedback opening (S3) that controls the opening of the bath mixing valve 28 based on the temperature detected by the filling temperature sensor 32. Then, the filling operation control means 36 checks whether there is any remaining hot water in the bathtub 31 after the predetermined amount of water filling operation (S5).

[0040] If there is no remaining hot water (S6 is Yes), the opening control means 35 controls the opening of the medium temperature water mixing valve 5 so that the high temperature side connected to the top of the hot water storage tank 2 is 100% and the medium temperature side connected to the middle of the hot water storage tank 2 is 0% (S7), and starts a water filling operation of a predetermined amount (here, 5 L) with a feedback opening that controls the opening of the bath mixing valve 28 based on the temperature detected by the water filling temperature sensor 32 (S8) (S9).

[0041] When the water filling operation with a predetermined amount of water (here, 5 L) is completed, the opening control means 35 switches the medium temperature water mixing valve 5 to an opening that actively uses medium temperature water (here, a feedforward opening) (S10), and sets the opening of the bath mixing valve 28 to the feedforward opening (S11).

[0042] The filling operation control means 36 starts a filling operation of 170L, which is the amount of water previously filled (here, 10L = 5L + 5L), so as to reach a predetermined bath set amount (here, 180L) (S12).

[0043] When the bathtub 31 reaches the set bath volume and set bath temperature (Yes in S13), the filling operation control means 36 completes the filling operation (S14).

[0044] Here, an embodiment for removing air from the upper part of the hot water tank 2 will be described in detail. Since the air in the hot water storage tank 2 accumulates at the top of the hot water storage tank 2, the opening degree of the medium temperature side of the medium temperature water mixing valve 5, which does not contribute to the discharge of air, is set to 0%, and the opening degree of the high temperature side of the medium temperature water mixing valve 5, which can discharge air, is set to 100%, so that the air in the hot water storage tank 2 can be efficiently discharged into the bathtub 31.

[0045] In addition, at the beginning of the filling operation, only the air accumulated at the top of the hot water storage tank 2 is discharged from the medium temperature water mixing valve 5, so the temperature detected by the filling temperature sensor 32 is the temperature of the water supply from the water supply bypass pipe 7. Therefore, by controlling the opening of the bath mixing valve 28 using a feedback opening, the opening of the medium temperature water mixing side of the bath mixing valve 28 opens widely because the filling temperature detected by the filling temperature sensor 32 does not meet the set bath temperature, and the air accumulated at the top of the hot water storage tank 2 is discharged from the medium temperature water mixing valve 5, making it easier to escape.

[0046] In this way, air accumulated in the upper part of the hot water storage tank 2 can be discharged into the bathtub 31 during a predetermined amount of filling operation at the beginning of the filling operation, so that air can be safely discharged into the bathtub 31 at the beginning of the filling operation when there is no one in the bathtub 31 yet, and air accumulated in the upper part of the hot water storage tank 2 can be completely discharged at the beginning of the filling operation.

[0047] In addition, by opening the medium temperature water mixing valve 5 100% on the high temperature side and opening the bath mixing valve 28 at a feedback degree, the air that has accumulated at the top of the hot water storage tank 2 can be quickly removed.

[0048] Also, if there is remaining hot water (S6 is No), the opening control means 35 controls the opening of the medium temperature water mixing valve 5 so that the high temperature side connected to the top of the hot water storage tank 2 is 100% and the medium temperature side connected to the middle of the hot water storage tank 2 is 0% (S16), and the opening of the bath mixing valve 28 is controlled by a feedback opening based on the temperature detected by the filling temperature sensor 32 (S17), and a predetermined amount of hot water filling operation (here, 5 L) is started (S18).

[0049] When the water filling operation with a predetermined amount of water (here, 5 L) is completed, the opening control means 35 switches the medium temperature water mixing valve 5 to an opening that actively uses medium temperature water (here, a feedforward opening) (S19), and sets the opening of the bath mixing valve 28 to the feedforward opening (S20).

[0050] The water filling operation control means 36 starts a water filling operation (water refilling operation) with an amount of water obtained by subtracting the amount of water previously filled from the amount of water remaining in the bathtub 31 so as to reach a predetermined bath set amount (here, 180 L) (S21).

[0051] When the bathtub 31 reaches the set bath volume and set bath temperature (Yes in S22), the filling operation control means 36 completes the filling operation (S23).

[0052] In this way, if there is residual hot water, the air that has accumulated at the top of the hot water storage tank 2 can be completely discharged into the bathtub 31 at the beginning of the water filling operation (water replenishment operation), thereby preventing the user from feeling uncomfortable due to the bubbling sound caused by air being discharged into the bathtub 31 while bathing.

[0053] Next, the operation when hot water supply operation is in progress when a predetermined amount of hot water filling is started, or when hot water supply operation is in progress and a predetermined amount of hot water filling is started, will be explained based on the flowchart in Figure 3. If hot water supply operation is in progress when the specified amount of hot water filling is started, or if hot water supply operation is in progress and a specified amount of hot water filling is started simultaneously (S24 is Yes), the opening control means 35 opens the medium temperature water mixing valve 5 to an opening that actively uses medium temperature water (here, feedforward opening) and fills the specified amount of hot water (S25).

[0054] If the user ends the hot water supply operation during simultaneous use (Yes in S26), the opening control means 35 checks whether the predetermined amount of hot water is being filled (S27).

[0055] If the specified amount of water filling is continuing (S27 is Yes), the opening control means 35 sets the opening of the medium temperature water mixing valve 5 to 100% on the high temperature side (S28), and the opening of the bath mixing valve 28 is set to a feedback opening that controls the opening based on the temperature detected by the water filling temperature sensor 32 (S29), and the water filling operation control means 36 continues filling the specified amount of water (S30).

[0056] Also, if the predetermined amount of water filling has been completed (No in S27), the water filling operation control means 36 continues the water filling operation with the medium temperature water mixing valve 5 kept at the feedforward opening degree (S30).

[0057] In this way, if the medium temperature water mixing valve 5 is opened 100% on the high temperature side to expel the air from the top of the hot water storage tank 2, high temperature water will be mixed in from the medium temperature water mixing side of the hot water mixing valve 8, preventing the user from feeling uncomfortable due to a sudden supply of high temperature water.

[0058] The present invention is not limited to the embodiments, and modifications may be made without departing from the spirit and scope of the invention. For example, in the embodiment, the pressure relief valve 27 is provided in the heating bypass pipe 25, but the pressure relief valve 27 may be provided in the water supply pipe 6 connected to the lower part of the hot water tank 2.

[0059] Furthermore, when the opening control means 35 is setting the opening of the bath mixing valve 28 to a feedback opening calculated from the filling temperature during a specified amount of water filling operation, the air that has accumulated at the top of the hot water storage tank 2 will first flow into the bath mixing valve 28. At this time, the bath mixing valve 28 mixes the air that has accumulated at the top of the hot water storage tank 2 with the water supply bypass pipe 7 on the bath mixing valve 28 side, so that the filling temperature detected by the filling temperature sensor 32 is lower than the bath set temperature and hot water is supplied to the bathtub 31. Therefore, under normal feedback opening control, the medium temperature water mixing side is opened widely to raise the filling temperature detected by the filling temperature sensor 32.

[0060] Then, when the air that has accumulated at the top of the hot water storage tank 2 has been completely released, the hot water at the top of the hot water storage tank 2 flows into the bath mixing valve 28. At this time, the medium temperature water mixing side of the bath mixing valve 28 is opened widely due to feedback opening control, so the bath filling temperature will overshoot significantly, so by setting a predetermined upper limit opening for the opening of the medium temperature water mixing side of the bath mixing valve 28 (here, 75% opening for the medium temperature water mixing side and 25% opening for the water supply side), it is possible to limit the sudden overshoot in the temperature of the hot water supplied to the bathtub 31. This predetermined upper limit opening is an opening that has been experimentally calculated to mitigate the overshoot.

[0061] In addition, when hot water supply operation and a specified amount of water filling operation are used simultaneously, unexpected high temperature water is prevented by mixing the medium temperature water mixing valve 5 at a feedforward opening degree. However, if the user wishes to prioritize the discharge of air from the top of the hot water storage tank 2, the medium temperature water mixing valve 5 can be set to 100% on the high temperature side even when they are used simultaneously, and the bath mixing valve 28 can be left at its feedback opening degree, thereby ensuring that the air is discharged. The discharge destination is the bathtub 31, and the opening degree of the medium temperature water mixing side of the bath mixing valve 28 is controlled so as not to exceed a specified upper limit opening degree, thereby achieving both air discharge and safety.

[0062] In addition, in the embodiment of the present invention, the opening degree for actively using medium temperature water has been described as a feedback opening degree, but the medium temperature water mixing valve 5 may also use a fixed opening degree, such as 100%, on the medium temperature side, and by reducing the medium temperature water in the hot water storage tank 2, the boiling efficiency of the boiling operation can be improved. [Explanation of symbols]

[0063] 2 Hot water tank 3 High temperature outlet pipe 4. Medium temperature outlet pipe 5. Medium temperature water mixing valve 6 Water supply pipe 7. Water supply bypass pipe 8 Hot water mixing valve 27 Pressure relief valve 28 Bath Mixing Valve 29 Water filling valve 30 Hot water pipe 31 Bathtub 34 Control device 35 Opening control means 36 Filling operation control means 46 Hot water temperature sensor 46a Upper tank temperature sensor 46b Intermediate hot water storage temperature sensor 47 Mixed water temperature sensor 48 Water supply temperature sensor

Claims

1. A hot water storage tank for storing hot water; A water supply pipe connected to a lower portion of the hot water storage tank; A heating means for heating the hot water in the hot water storage tank; A heating pipe that delivers water from a lower portion of the hot water storage tank to the heating means; A heat return pipe that delivers the heat from the heating means to an upper portion of the hot water storage tank; a pressure relief valve provided in a pipe connected to a lower portion of the hot water storage tank, for releasing pressure to the outside of the hot water storage tank when the pressure in the hot water storage tank exceeds a predetermined pressure; A water supply bypass pipe branched off from the water supply pipe; a medium-temperature water mixing valve for mixing high-temperature water taken out from an upper portion of the hot water storage tank and medium-temperature water taken out from a middle portion of the hot water storage tank; a bath mixing valve that mixes the medium-temperature water mixed by the medium-temperature water mixing valve with water supplied from the water supply bypass pipe and supplies the mixed water to a bathtub; a hot water mixing valve that mixes the medium-temperature water mixed in the medium-temperature water mixing valve with water supplied from the water supply bypass pipe and supplies the mixed water to a hot water tap; A bath temperature sensor for detecting a bath temperature of the hot water mixed by the bath mixing valve; A bath filling path that supplies mixed water mixed by the bath mixing valve to the bathtub; In a hot water storage type hot water supply device having a control device provided with a hot water filling operation control means for performing a hot water filling operation in which a predetermined amount of hot water is supplied to the bathtub through the hot water filling path, and an opening control means for controlling the opening of the medium temperature water mixing valve and the bath mixing valve, When the water filling operation is started, the opening control means fully opens the medium temperature water mixing valve to the high temperature side, and the opening of the bath mixing valve is set to a feedback opening calculated from the water filling temperature, and the water filling operation control means performs a predetermined amount of water filling operation, This storage type hot water supply device is characterized in that when the specified amount of hot water filling is completed, the opening control means switches the opening of the medium temperature water mixing valve to an opening that actively uses the medium temperature water, and the hot water filling operation control means performs hot water filling operation until the set hot water filling amount is reached.

2. When the hot water supply operation of the hot water supply mixing valve and the bath mixing valve are used simultaneously, the opening control means switches the opening of the medium temperature water mixing valve to an opening that actively uses the medium temperature water, and fills the bath with the predetermined amount of hot water, A storage type hot water supply device as described in claim 1, characterized in that when the hot water supply operation is terminated in the middle of filling the tank with the specified amount of hot water, the opening control means opens the medium temperature water mixing valve fully to the high temperature side so as to continue filling the tank with the specified amount of hot water.

3. 3. The storage type hot water supply device according to claim 1, wherein the opening control means prevents the opening of the medium temperature water mixing side of the bath mixing valve from exceeding a predetermined upper limit opening.

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